If present, this is a folder that is added by the browser and that cannot
be modified by the user or the extension. Child nodes may be modified, if
this node does not have the unmodifiable property set. Omitted if the
node can be modified by the user and the extension (default).There may be
zero, one or multiple nodes of each folder type. A folder may be added or
removed by the browser, but not via the extensions API.
Whether this node is synced with the user's remote account storage by the
browser. This can be used to distinguish between account and local-only
versions of the same FolderType. The value of this property may change
for an existing node, for example as a result of user action.Note: this
reflects whether the node is saved to the browser's built-in account
provider. It is possible that a node could be synced via a third-party,
even if this value is false.
Indicates the reason why this node is unmodifiable. The managed value
indicates that this node was configured by the system administrator or by
the custodian of a supervised user. Omitted if the node can be modified by
the user and the extension (default).